3 Ways Your Body Sabotages Your Money

Humans share a common delusion when it comes to our actions: We like to believe that it’s our brains running the show, and our bodies are just along for the ride. We trust our little gray cells to do the work of making sure we stick to the straight-and-narrow path while we are trying to reach our personal and financial goals.

The problem is that our bodies have an impressive ability to sabotage all the good intentions of our brains. Before you assume that your cerebellum is up to the task of resisting your body’s sabotage, remember that the following things can crush even the strongest of good intentions into dust. (See also: 5 Mental Biases That Are Keeping You Poor)

Hunger saps your willpower

Those candy bar commercials are quite right when they point out that you’re not you when you’re hungry. While everyone has experienced the irritability associated with being a little “hangry,” what you might not realize is that your low blood sugar is also depleting your ability to withstand temptation.

According to a 2007 self-control study by Matthew T. Gailliot and Roy F. Baumeister, your ability to exert self-discipline depends partially on your blood-glucose levels. This is the sort of thing that feels obvious when you go grocery shopping on an empty stomach, since you’re feeling tempted by the very thing you lack. However, the relationship between self-discipline and blood-glucose levels is also behind your struggle to avoid other types of temptations. That’s because, according to the researchers, “self-control requires a certain amount of glucose to operate unimpaired.”

This is why it’s much harder to avoid making impulse purchases when you’re hungry. For instance, I recently forgot to grab a snack for myself right before taking my son to his weekly swim lesson. While I waited by the pool with my stomach rumbling, I found myself purchasing two new audiobooks from Audible on my phone, despite my commitment to refrain from spending more money on audiobooks. My willpower was destroyed by my hunger pangs.

That’s why I try to always carry a piece of fruit or other complex carbohydrate with me while I’m out. (That, and you wouldn’t like my kids when they are hangry.) Having a quick snack can often nip temptations in the bud before they have a chance to disrupt your good financial intentions.

Lack of sleep impairs your judgment

We’ve all known the fuzzy feeling in our heads after an all-nighter. Since the wooziness disappears once you’ve gotten some sleep, we all tend to ignore the effects of sleeplessness since they are relatively short lived. After all, no one goes for days on end without sleep.

Unfortunately, sleep deprivation has a much bigger effect on your cognitive abilities than you might realize. A 2000 study by A.M. Williamson and Anne-Marie Feyer found that going without sleep for 20 or more hours straight makes a person perform tasks as if they had a blood alcohol level of 0.1 percent, which is 0.02 percent over the legal limit for driving under the influence. The study was looking at how non-sleepers do while performing tasks requiring both speed and accuracy — such as the tasks necessary to drive a car.

Of course, most people are not going without sleep for 20 hours. However, even a built-up sleep deficit accumulated by regularly getting only four or five hours of sleep per night can affect your mental acuity. In a 2006 interview with The Harvard Business Review, Dr. Charles A. Czeisler, the Baldino Professor of Sleep Medicine at Harvard Medical School wrote, “[if you] average four hours of sleep a night for four or five days, [you] develop the same level of cognitive impairment as if [you’d] been awake for 24 hours.”

So what does this mean for your financial goals? Nothing good, I’m afraid. Your ability to make rational financial decisions is also seriously impaired when your mental acuity is suffering from sleep deprivation. Your sleep-deprived brain is less able to fulfill the sorts of executive functions necessary to predict outcomes and perceive the consequences of actions — which means you are more likely to make poor financial decisions when you are exhausted.

Arousal can erode your moral compass

You might believe that your morality is an integral part of who you are, but behavioral economists have shown that our belief systems can be thwarted when our bodies want something. With a racy experiment, author and researcher Dan Ariely demonstrated in his book Predictably Irrational that our commitment to various strongly-held beliefs decreases when we are in a state of sexual arousal.

Ariely’s experiment asked college-aged men how they felt about issues like fairness, gender equality, and safe sex. During the control “cold” state, these young men expressed commitment to moral, ethical, and responsible behavior. But after being exposed to sexual imagery, and entering into what scientists call a “hot” state, their beliefs were much more malleable.

This malleability of beliefs is not confined to sexual arousal. The hot-cold empathy gap is the name for this change in behavior due to any number of bodily needs. The empathy gap describes the way in which it is difficult for someone who is not currently experiencing something like hunger, pain, or sexual arousal to recognize how much these states can affect their decisions. For instance, in a separate study, respondents in a 2003 survey were much likelier to rate thirst rather than hunger as the most unpleasant aspect of being lost in the woods if the respondents had just finished a cardio workout and were therefore thirsty. If they had not yet started their workout, the respondents rated hunger as being more unpleasant.

This kind of empathy gap is the reason why we often wrongly predict that we will be able to resist temptation in the moment. When we are not currently faced with a temptation, we imagine ourselves as being the most rational and moral version of ourselves. But feeling hunger, pain, arousal, thirst, or other overwhelming bodily needs weakens our commitments to good behavior.

In terms of your finances, that means an overwhelming thirst (or other need) could prompt you to spend money you had no intention of spending.

Outwitting your body

The good news is that just because our bodies do have the ability to override our brains, we are still smarter than our impulses. The trick is to recognize that you are not always the best version of yourself, and plan ahead for those moments.

Carry snacks with you to make sure your blood-glucose level doesn’t drop to finance-sabotaging depths. Make sure you get adequate sleep, and hide your credit cards when you know you’ll have a few nights of sleeplessness. Assume that you’re going to be the worst version of yourself when you’re in pain, aroused, hungry, thirsty, or craving sugar. If you recognize that you’ll have trouble avoiding temptation in those states, it’s easier to structure activities so that you don’t come into contact with temptations during those times at all.

The most disciplined and intelligent savers aren’t necessarily better at exerting willpower. They just know that they won’t always be perfect, and they plan ahead for when their bodies, rather than their brains, are behind the wheel.